(1) Field of the Invention
The present invention relates to an image forming apparatus, in particular, relating to an image forming apparatus that is controlled to perform image output based on electrophotography.
(2) Description of the Prior Art
Recently, image forming apparatuses such as copiers, facsimile machines and the like, are configured to be able to easily perform image output by remote control from external devices such as PC terminals and the like. The documents output from the image forming apparatus can be usually stacked on the paper output tray and collected in a simple manner.
However, the documents on this paper output tray are exposed to the state in which any one can easily pick them up or any one can easily look the recorded content of the documents.
Under such circumstances, conventionally there has been a proposal of an image forming apparatus having the function of preventing illegal copy in order that an original copy and output copy will not be duplicated. For example, there is a disclosure of an image forming apparatus, in which, when confidential printing is designated, printing is carried out on the interior side of a recording sheet, and the recording sheet is saddle stitched by stapling so that the content printed on the interior side of the recording paper cannot be seen easily (see patent document 1: Japanese Patent Application Laid-open 2004-322342).
Though the conventional technology described above can prevent illegal copy by stapling confidential print sheets, it is still possible to grasp the content of the printed documents easily even when they remain being stapled. As a result, the above configuration still entails the problem that information leakage cannot be prevented.